Various gas nozzles, which have different external or internal contours, differently shaped nozzle openings, and different nozzle diameters, are required for machining (for example, cutting or welding) different materials (e.g., construction steel, stainless steel, aluminum, etc.) of different material thicknesses with the aid of a laser beam.
A gas nozzle having an inner nozzle through which a laser beam and a cutting gas are directed onto a workpiece is known from WO 2014/072609 A1. A sleeve is guided so as to be axially displaceable in an annular gap that surrounds an inner nozzle of the gas nozzle, wherein the sleeve is pre-tensioned to a rearward end position thereof by a spring. The rear end side of the sleeve in the annular gap delimits an annular space that is connected to a nozzle bore of the inner nozzle by way of connection openings. The higher the cutting gas pressure, the further the sleeve is advanced forward, counter to the restoring force of the spring. The sleeve is guided in the gas nozzle body both on the external side on a cap as well as on the internal side on a tubular element so as be axially displaceable. The sleeve on the front end face of the sleeve on the external side can have a run-up slant to be able to slide without damage across minor steps in the workpiece surface, such as can arise by the tilting of workpiece parts that have been cut off, for example.